Drivetrain rattle

[crazyb1]

I started my Z and immediately got a rattle that sounds similar to an A/C bearing going out. I turned A/C off and rattle remained. I listened from under the car and the noise is louder there (like it's coming from the headers). Pushing in the clutch changes the pitch of the rattle very slightly. The engine doesn't seem down on hp. and runs as smoothly as before. When increasing rpm, it doesn't seem (I may be wrong) that the rattle increases in pitch, volume, etc. I've thought about the alternator, A/C, and now the ZF as the culprit. 50K miles. Any ideas?

[Sgreg]

I think I would check the exhaust system including heat shieds all the way back. When a little loose, these items can cause a bunch of noise particularly under the car. Less likely but worth a look are engine mounts. Good luck.

[guinnessdood]

I started my Z and immediately got a rattle that sounds similar to an A/C bearing going out. I turned A/C off and rattle remained. I listened from under the car and the noise is louder there (like it's coming from the headers). Pushing in the clutch changes the pitch of the rattle very slightly. The engine doesn't seem down on hp. and runs as smoothly as before. When increasing rpm, it doesn't seem (I may be wrong) that the rattle increases in pitch, volume, etc. I've thought about the alternator, A/C, and now the ZF as the culprit. 50K miles. Any ideas?
Sounds like it could be the pilot bearing. Contact Bill Boudreau and descrieb the sound or record the sound and send it to him. www.zfdoc.com is his website...Great Guy!

[crazyb1]

After listening to the motor again, the sound is more of a tapping/clicking sound, not like something is loose (rattling). If this is the heat shield, what should I be looking for? Loose fitting? Will the pilot bearing make a tapping/ticking noise if going out?

[Sgreg]

When I have had a pilot bearing problem , it squealed badly like a slipping fan belt. I wouldn't call it a rattle or clicking sound.. Clicking and tapping noise could be a lifter but if it's coming from underneath the car still sounds like a loose piece of exhaust. The pulsing of an exhaust causes quite a bit of vibration if everything is not secured well.

[tccrab]

Bearings typically don't make a tap or a rattle sound.
They squeal.
Could it be this?
http://www.zr1netregistry.com/forum/showthread.php?t=2294

For your sake, I hope not... :pray

Make a recording of the sound and let us give it a listen.
Here's hoping it's something simple...

TomC
'90ZR1 #792

[Belsy]

Could it be your cat converters? They can break loose inside I believe.

[Sgreg]

As long as we are guessing, how about the pressure plate or throw-out bearing ? :rolleyes: Very hard to diagnose without being there.